Immunity

Question 1

What happens in cell-mediated immunity?

Answer 1

T lymphocytes respond to the cells of an organism that has been changed in some way

important in early cancers and viruses

Question 2

What are the stages in cell-mediation immunity

Answer 2

1. Macrophages become APCs
2. The receptors on some of the T helper cells fit the antigens on the APC, these become activated and produce interleukins
3. This stimulates more T cells to divide rapidly by mitosis
4. They form clones of identiacal T cells that all carry the right antigen to bind to a pathogen

Question 3

What is the purpose of the cloned T cells?

Answer 3

• develop into T memory cells, which give a rapid response if this pathogen invades the body again
• produce interleukins that stimulate phagocytosis or stimulate B cells to divide
  
  • stimulate the development of a clone of T killer cells that are specific for the presented antigen and destroy infectedf cells

Question 4

What is humoral immunity?

Answer 4

the body responds to antigens found outside of cells

important for bacteria and fungi and to APCs

the humoral system produces antibodies that are soluble in the blood and tissue fluid that are not attached to cells

Question 5

How does a B lymphocyte become an APC?

Answer 5

a B cell with complementary antibodies will bind to the antigens on the pathogen, or to the free antigens

the B cells engulfs and processes the antigen to become an APC?

Question 6

Humoral immunity stages 1-3: what is clonal selction and clonal expansion?

Answer 6

1. Activated T helper cells bind to the B cell APC - this is clonal selection - the point at which the B cell with the correct antibody to overcome a particular antigen is selected for cloning
2. Interleukins produced by the activated T helper cells activate the B cells
3. The activated B cells divides by mitosis to give clones of plasma cells and B memory cells - this is clonal expansion

Question 7

Humoral immunity stages 3-4: What is the primary and secondary immune response?

Answer 7

• Cloned plasma cells produce antibodies that fit the antigens on the surface of the pathogen, these bind to the antigens and disable them, or act as opsonins or agglutinins - this is the primary immune response (it can take days or weeks to become effective against a particular pathogen)
  
  • Some cloned B cells develop into B memory cells - if the body is infected by the same pathogen again, the B memory cells divide rapidly to form plasma cell clones - these produce the right antibody and wipe out the pathogen very quickly, before it can cause symptoms of disease - this is the secondary immune response

Question 8

What is an autoimmune disease?

Answer 8

immune systems stops recognising ‘self’ cells and attacks healthy body tissue

caused by genetic factors

treated with immunosupressent drugs - this deprives the body of defences against communicable diseases

Question 9

Type 1 diabetes - what part of the body is affected and what is the treatment?

Answer 9

• insulin secreting cells of the pancreas
• insulin injections
• pancreas transplant
• immunosupressent drugs

Question 10

Rheumatoid arthritis - what body part is affected and what is the treatment?

Answer 10

• joints - especially in hands, wrists, ankles and feet
  
  • anti-inflammatory drugs
  • steroids
  • immunosupressents
  • paint relief
  • no cure

Question 11

Lupus - what body part is affected and what is the treatment?

Answer 11

• often affects skin and joint and causes fatigue
  
  • can attack any organ in the body
• anti-inflammatory drugs
• steroids
• immuosupressents
• no cure